bug#58216: 28.2; New help-for-help hides user key bindings

bug#58216: 28.2; New help-for-help hides user key bindings

[Allen Li]

The new `help-for-help' bound to C-h C-h hides the user's key bindings.

I have bound a couple of commands to the C-h prefix to provide some
personalized help and occasionally I would type C-h C-h to double check
which commands I have bound, for some of the less frequently used ones.

Previously, this would show the normal prefix help which describes all
keys in the prefix map.  However, the new `help-for-help' does not do
so.

I suggest that the `help-for-help' command include any custom bindings
in the prefix map as a separate "Custom" section at the end so they can
still be found.

In GNU Emacs 28.2 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.34, cairo version 1.17.6)
 of 2022-09-12 built on frederik
Windowing system distributor 'The X.Org Foundation', version 11.0.12101004
System Description: Arch Linux

bug#58216: 28.2; New help-for-help hides user key bindings

[Stefan Kangas]

Allen Li <darkfeline@felesatra.moe> writes:

> The new `help-for-help' bound to C-h C-h hides the user's key bindings.

Thanks for the bug report, I will look into it.  Meanwhile, it would
help if you could provide a recipe to reproduce it.

bug#58216: 28.2; New help-for-help hides user key bindings

[Allen Li]

Stefan Kangas <stefankangas@gmail.com> writes:

> Allen Li <darkfeline@felesatra.moe> writes:
>
>> The new `help-for-help' bound to C-h C-h hides the user's key bindings.
>
> Thanks for the bug report, I will look into it.  Meanwhile, it would
> help if you could provide a recipe to reproduce it.

1. emacs -Q
2. (define-key [?\C-h ?M] #'man)
3. C-h C-h

Expected:

Help shows the C-h M binding

Actual:

Help does not show the C-h M binding

bug#58216: 28.2; New help-for-help hides user key bindings

[Stefan Kangas]

Allen Li <darkfeline@felesatra.moe> writes:

> 1. emacs -Q
> 2. (define-key [?\C-h ?M] #'man)

That doesn't work, so I interpreted this as:

    (global-set-key [?\C-h ?M] #'man)

> 3. C-h C-h

With the above (adjusted) recipe on Emacs 27.1, my " *Metahelp*" buffer
contains the below text.  I don't see the `C-h M' binding in there.

I also tried replacing step 2 with this instead

    (define-key help-map [?M] #'man)

but I still couldn't see `C-h M' in there.

What am I missing?  Could you provide the full text of your
" *Metahelp*" buffer (or a screenshot) with the above recipe?

    You have typed C-h, the help character.  Type a Help option:
    (Use SPC or DEL to scroll through this text.  Type q to exit the
Help command.)

    a PATTERN   Show commands whose name matches the PATTERN (a list of words
                  or a regexp).  See also the ‘apropos’ command.
    b           Display all key bindings.
    c KEYS      Display the command name run by the given key sequence.
    C CODING    Describe the given coding system, or RET for current ones.
    d PATTERN   Show a list of functions, variables, and other items whose
                  documentation matches the PATTERN (a list of words
or a regexp).
    e           Go to the *Messages* buffer which logs echo-area messages.
    f FUNCTION  Display documentation for the given function.
    F COMMAND   Show the Emacs manual’s section that describes the command.
    g           Display information about the GNU project.
    h           Display the HELLO file which illustrates various scripts.
    i           Start the Info documentation reader: read included manuals.
    I METHOD    Describe a specific input method, or RET for current.
    k KEYS      Display the full documentation for the key sequence.
    K KEYS      Show the Emacs manual’s section for the command bound to KEYS.
    l           Show last 300 input keystrokes (lossage).
    L LANG-ENV  Describes a specific language environment, or RET for current.
    m           Display documentation of current minor modes and
current major mode,
                  including their special commands.
    n           Display news of recent Emacs changes.
    o SYMBOL    Display the given function or variable’s documentation
and value.
    p TOPIC     Find packages matching a given topic keyword.
    P PACKAGE   Describe the given Emacs Lisp package.
    r           Display the Emacs manual in Info mode.
    s           Display contents of current syntax table, plus explanations.
    S SYMBOL    Show the section for the given symbol in the Info manual
                  for the programming language used in this buffer.
    t           Start the Emacs learn-by-doing tutorial.
    v VARIABLE  Display the given variable’s documentation and value.
    w COMMAND   Display which keystrokes invoke the given command (where-is).
    .           Display any available local help at point in the echo area.

    C-a         Information about Emacs.
    C-c         Emacs copying permission (GNU General Public License).
    C-d         Instructions for debugging GNU Emacs.
    C-e         External packages and information about Emacs.
    C-f         Emacs FAQ.
    C-m         How to order printed Emacs manuals.
    C-n         News of recent Emacs changes.
    C-o         Emacs ordering and distribution information.
    C-p         Info about known Emacs problems.
    C-s         Search forward "help window".
    C-t         Emacs TODO list.
    C-w         Information on absence of warranty for GNU Emacs.

bug#58216: 28.2; New help-for-help hides user key bindings

[Lars Ingebrigtsen]

Stefan Kangas <stefankangas@gmail.com> writes:

> I also tried replacing step 2 with this instead
>
>     (define-key help-map [?M] #'man)
>
> but I still couldn't see `C-h M' in there.

That's what he wants to have fixed -- he wants to see `C-h M' in that
buffer.

bug#58216: 28.2; New help-for-help hides user key bindings

[Stefan Kangas]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> Stefan Kangas <stefankangas@gmail.com> writes:
>
>> I also tried replacing step 2 with this instead
>>
>>     (define-key help-map [?M] #'man)
>>
>> but I still couldn't see `C-h M' in there.
>
> That's what he wants to have fixed -- he wants to see `C-h M' in that
> buffer.

So this is a feature request?  I interpreted it as a regression, based
on this in the original bug report:

    The new `help-for-help' bound to C-h C-h hides the user's key bindings.

    I have bound a couple of commands to the C-h prefix to provide some
    personalized help and occasionally I would type C-h C-h to double check
    which commands I have bound, for some of the less frequently used ones.

    Previously, this would show the normal prefix help which describes all
    keys in the prefix map.  However, the new `help-for-help' does not do
    so.

bug#58216: 28.2; New help-for-help hides user key bindings

[Lars Ingebrigtsen]

Stefan Kangas <stefankangas@gmail.com> writes:

>> That's what he wants to have fixed -- he wants to see `C-h M' in that
>> buffer.
>
> So this is a feature request?  I interpreted it as a regression, based
> on this in the original bug report:
>
>     The new `help-for-help' bound to C-h C-h hides the user's key bindings.
>
>     I have bound a couple of commands to the C-h prefix to provide some
>     personalized help and occasionally I would type C-h C-h to double check
>     which commands I have bound, for some of the less frequently used ones.
>
>     Previously, this would show the normal prefix help which describes all
>     keys in the prefix map.  However, the new `help-for-help' does not do
>     so.

It's a regression that `C-h M' isn't shown any more, and he requests a
new feature that would show it in a way that fits the new `C-h C-h'
display.

bug#58216: 28.2; New help-for-help hides user key bindings

[Stefan Kangas]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> It's a regression that `C-h M' isn't shown any more,

Was `C-h M' displayed before though?

I thought that is what I tested, and the result was that it was not
shown.  Did I make a mistake in my testing, or did I miss something?

> and he requests a new feature that would show it in a way that fits
> the new `C-h C-h' display.

This part is clear, thank you.

bug#58216: 28.2; New help-for-help hides user key bindings

[Lars Ingebrigtsen]

Stefan Kangas <stefankangas@gmail.com> writes:

>> It's a regression that `C-h M' isn't shown any more,
>
> Was `C-h M' displayed before though?

Ah, no, I guess it wasn't.

bug#58216: 28.2; New help-for-help hides user key bindings

[Allen Li]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> Stefan Kangas <stefankangas@gmail.com> writes:
>
>>> It's a regression that `C-h M' isn't shown any more,
>>
>> Was `C-h M' displayed before though?
>
> Ah, no, I guess it wasn't.

Before the recent binding of C-h C-h to help-for-help, C-h C-h was
unbound and thus used the default behavior of printing help for all keys
bound to the prefix map.  As an example see the behavior for C-x C-h.
If the user bound a key with C-h prefix, that binding previously would
show up in C-h C-h help.

Example:

User binds C-h M

Before help-for-help was introduced:

C-h C-h would display the user-bound C-h M mapping

After help-for-help was introduced:

C-h C-h does not display any user mappings with C-h prefix

See https://www.gnu.org/software/emacs/manual/html_node/emacs/Keys.html

    Typing the help character (C-h or F1) after a prefix key displays a list
    of the commands starting with that prefix. The sole exception to this
    rule is ESC: ESC C-h is equivalent to C-M-h, which does something else
    entirely. You can, however, use F1 to display a list of commands
    starting with ESC.

bug#58216: 28.2; New help-for-help hides user key bindings

[Lars Ingebrigtsen]

Allen Li <darkfeline@felesatra.moe> writes:

> Before the recent binding of C-h C-h to help-for-help, C-h C-h was
> unbound and thus used the default behavior of printing help for all keys
> bound to the prefix map.

I checked Emacs 26.1 --

C-h C-h runs the command help-for-help (found in global-map), which is
an alias for ‘help-for-help-internal’ in ‘help.el’.

Which Emacs version do you see `C-h C-h' not bound to `help-for-help'?

bug#58216: 28.2; New help-for-help hides user key bindings

[Stefan Kangas]

severity 58216 wishlist
thanks

Allen Li <darkfeline@felesatra.moe> writes:

> Before the recent binding of C-h C-h to help-for-help, C-h C-h was
> unbound

AFAICT, that key binding has been the same since at least:

    commit 433ae6f6e191af1d1bc67025200ea54a08761e68
    Author: Richard M. Stallman <rms@gnu.org>
    Date:   Sun Aug 25 21:47:10 1991 +0000

        Initial revision

Which says:

    (define-key global-map "\C-h" 'help-command)
    (fset 'help-command help-map)
    (define-key help-map "\C-h" 'help-for-help)

> and thus used the default behavior of printing help for all keys
> bound to the prefix map.  As an example see the behavior for C-x C-h.
> If the user bound a key with C-h prefix, that binding previously would
> show up in C-h C-h help.

That's not what I see in Emacs 27.1.  Have you tried it in "emacs -Q"?

bug#58216: 28.2; New help-for-help hides user key bindings

[Allen Li]

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On Mon, Oct 3, 2022 at 2:20 AM Stefan Kangas <stefankangas@gmail.com> wrote:

> severity 58216 wishlist
> thanks
>
> Allen Li <darkfeline@felesatra.moe> writes:
>
> > Before the recent binding of C-h C-h to help-for-help, C-h C-h was
> > unbound
>
> AFAICT, that key binding has been the same since at least:
>
>     commit 433ae6f6e191af1d1bc67025200ea54a08761e68
>     Author: Richard M. Stallman <rms@gnu.org>
>     Date:   Sun Aug 25 21:47:10 1991 +0000
>
>         Initial revision
>
> Which says:
>
>     (define-key global-map "\C-h" 'help-command)
>     (fset 'help-command help-map)
>     (define-key help-map "\C-h" 'help-for-help)
>
> > and thus used the default behavior of printing help for all keys
> > bound to the prefix map.  As an example see the behavior for C-x C-h.
> > If the user bound a key with C-h prefix, that binding previously would
> > show up in C-h C-h help.
>
> That's not what I see in Emacs 27.1.  Have you tried it in "emacs -Q"?
>

Seems like I misremembered, sorry about that.  Then this is a feature
request not regression.

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bug#58216: 28.2; New help-for-help hides user key bindings

[Stefan Kangas]

Allen Li <darkfeline@felesatra.moe> writes:

> Seems like I misremembered, sorry about that.  Then this is a feature
> request not regression.

Thanks, that gives us more clarity about what needs doing.

This bug report is marked "wishlist", and I think patches are welcome.